Witchstalker

The witchstalker has advantage on saving throws against spells and other magical effects.

The witchstalker can sense the presence and location of magic within 120 feet of itself. It also has advantage on attack rolls against creatures that have cast a spell since the end of the witchstalker's last turn.

The witchstalker makes two Bite attacks.

Melee Weapon Attack +7 to hit, reach 5 ft., one target. 14 (3d6 + 4) Piercing damage. If the target is a Large or smaller creature, it must succeed on a DC 15 Strength saving throw or have the Prone condition.

The witchstalker unleashes a terrible howl, and each creature within 30 feet of it that isn't a Monstrosity must make a DC 13 Wisdom saving throw. On a failed save, a creature takes 24 (7d6) Psychic damage and has disadvantage on Constitution saving throws to maintain Concentration on spells until the end of its next turn. On a successful save, a creature takes half as much damage only.

Immediately after a creature within 120 feet of the witchstalker casts a spell, the witchstalker magically teleports to an unoccupied space within 5 feet of the creature and can make one Bite attack against the creature.